Preheat the oven to 400 F. Toss sweet potato rounds in olive oil and sprinkle with salt and pepper. Spread over a baking sheet and roast for 25 minutes, flipping once during cook time.
Cut the avocados in half. Remove the pit. Score the inside of the avocado with a blunt knife and scoop out the flesh with a spoon. Place in a bowl. Roughly mash the avocado with a fork.
Add the chopped onion, black pepper, salt, lime juice.
When potatoes are done roasted, remove from oven and top with a scoop of avocado, sliced tomatoes, and a sprinkle of sesame seeds.